Make-up of the epinephrine autoinjector: the effect on its use by untrained users

Part of the problems related to proper use of the epinephrine autoinjector may be related to the design of the autoinjector itself.

We investigated whether minor modifications in the design of the currently available epinephrine autoinjector ease its use and abrogate common use errors.

All interns other than those who had previously worked in allergy department in a medical school were invited to the study. Two identical epinephrine autoinjector trainers (Epipen trainer(®) ) were used, one of which was modified by changing the gray safety cap to red and placing a yellow arrow pointing to the black injection tip. A written and visual instruction sheet for each trainer was provided. Participants were asked to demonstrate the use of the Epipen trainer either with the original or with the modified one. They were scored and timed for their demonstration.

Out of the 224 interns who were invited to participate, one hundred and sixty-four interns (73.2%) participated in the study. The number of participants correctly demonstrating the use of epinephrine autoinjectors was 22.6% and 65% in unmodified and modified trainer groups, respectively (p < 0.001). The mean time to administer trainers was 26.78 ± 10.6 and 15.88 ± 2.55 s; total median scores were 3.08 ± 1.48 and 4.47 ± 0.84 in unmodified and modified groups, respectively (p < 0.001 for both). Significantly fewer participants had presumptive unintentional injection injury while using modified (5%) compared with unmodified trainer (45.2%) (p < 0.001).

Few and simple modifications in the design of epinephrine autoinjector were found effective in increasing its correct use and decreasing common use errors by untrained users. (Clinical trials identifier: NCT01217138).